Zeus botnet bank thieves focused on logistics of crime and not covering their tracks

Suspects charged with stealing more than $9.4 million from U.K. banks using the Zeus botnet apparently spent more time figuring out the logistics of stealing the money than they did on securing their cyber operation.

Criminal groups using Zeus commonly leave their command and control servers traceable and make use of servers in the same geographical area where they carry out theft, says Mickey Boodaei, CEO of browser security vendor Trusteer.

"They are not doing the best job of covering their tracks," Boodaei says. "Their own security is not at the top of their minds right now. They're focused on the operational side of getting money out of the banks."

Police in the U.K. have arrested 19 people on charges they used the Zeus trojan to break into customer accounts and steal funds by transferring it to other accounts held by accomplices who then delivered it to the masterminds via untraceable means like Western Union, he says.

Boodaei says his company has been tracking several groups using Zeus to steal money from online accounts and has no way of knowing whether the intelligence it gathered was used in the investigation that led to the recent U.K. arrests. His firm works for the banks and shares the intelligence with them, and they may or may not pass it along to police.

Trusteer has captured the malware used in the crime and managed to figure out the transactions it was designed to carry out. In some cases Trusteer has managed to find the command and control servers used to run the operation, the company claims.

In general, Zeus is available online and has tools for customizing it and building new versions to bypass specific security controls and adapt to changes banks implement to shore up their online services, Boodaei says.

"There are probably dozens of criminal groups that license Zeus," he says. "They're all separate, each has its own configuration. Some are focused on just a couple of banks." Their customized Zeus malware is tuned to attack specific banks.

Once investigators track down the command and control servers, they can follow transactions to the server and so trace the criminals, Boodaei says. "You don't use servers in the same territory where you're operating," he says.

Similarly, investigators can trace the accounts set up by the money mules – the people whose accounts receive the stolen funds then transfer them to the criminals. Once they are found, investigators can trace how they were recruited and perhaps by whom, he says.